How to hide Kubuntu apps from the Ubuntu desktop environment and the opposite?

Question

I am using Ubuntu 18.04 LTS and when I heard about KDE plasma 5.13 I decided to try it, and be able to use both DEs. However, I found my Ubuntu dock cluttered with KDE apps like Dolphin and Okular... I want each desktop environment to have its default built-in apps but I don't want it to have the other's. How do I go about that? I don't want to hide the apps manually, I would rather have a script take care of it. Any help would be greatly appreciated!

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Edit: I tried making a bash file to make KDE apps only visible in KDE after following instructions from a UNIX stackexchange post. Here is its content:

#!/bin/bash
cd /usr/share/applications/kde4/ || exit
sudo for i in *.desktop; do echo "OnlyShowIn=KDE" >> "$i"; done

and ran it with the following command: $ sudo bash default_apps_restricter.sh However, I got this output:

default_apps_restricter.sh: line 3: syntax error near unexpected token `do'
default_apps_restricter.sh: line 3: `sudo for i in *.desktop; do echo "OnlyShowIn=KDE" >> "$i"; done'

Please help!

Answer 1

You can edit the .desktop launcher associated to each application and add OnlyShowIn or NotShowIn keys accordingly. The .desktop files can be found in /usr/share/applications/ (and some in ~/.local/share/applications/).

But it's not recommended to edit the files in /usr/share/applications/ (they'll most likely be overwritten once an associated package gets updated). Instead copy the .desktop file from /usr/share/applications/ to ~/.local/share/applications/ and edit the copied file.

To make an application visible only in GNOME add the following line

OnlyShowIn=GNOME;

and to make an application invisible in GNOME add the following line

NotShowIn=GNOME;